Control de los síntomas en pacientes terminales: efectividad del tratamiento de la disnea irruptiva con opioides / Symptoms control in terminally ill patients: effectiveness of opioid treatment for breakthrough dyspnea

Introducción y objetivo: La disnea irruptiva (DI) se observa con mucha frecuencia en pacientes terminales. El objetivo principal de este estudio fue valorar el grado de control de los síntomas de los pacientes que acuden a nuestra unidad, con especial interés en la evaluación de la efectividad del tratamiento de la DI en pacientes terminales. Pacientes y métodos: Se realizó un estudio observacional sobre los datos de un registro de pacientes de una unidad de hospitalización domiciliaria. Se seleccionaron pacientes con enfermedad terminal con DI que fueron tratados con un opioide. La intensidad de la DI se valoró mediante la escala de Borg antes y después del tratamiento. Se evaluó la intensidad de otros síntomas mediante la escala ESAS (Edmonton Symptom Assessment System). Resultados: Se incluyeron 100 pacientes en el análisis. El 65 % de los pacientes eran hombres, siendo un 55 % pacientes oncológicos. Se administró fentanilo sublingual (71 %), fentanilo intranasal (18 %), fentanilo oral (1 %) y morfina subcutánea (10 %). El 94 % respondieron al tratamiento con mejoría de dos o más puntos en la escala de Borg. El perfil de seguridad fue aceptable en todos los casos. Conclusiones: A pesar de que en la primera línea de tratamiento de la DI se recomiendan los opioides, no existe suficiente grado de evidencia científica que justifique su uso. Se observó en el estudio que el tratamiento con fentanilo puede ser una opción terapéutica eficaz y segura para el control de la disnea irruptiva en pacientes terminales (AU)

Introduction and objective: Breakthrough dyspnea (BD) is frequently suffered by in terminally ill patients. The main objective of the study was to assess the degree of symptom control for patients admitted to our unit specially the effectiveness of BD therapy in terminally ill patients. Patients and methods: An observational study of a registry of patients was completed and performed at a Spanish hospice care unit. Terminally ill patients presenting with BD and having undergone opioid treatment were selected. BD’s intensity was measured prior to and after treatment using the Borg scale. The intensity of other symptoms was evaluated using the Edmonton Symptom Assessment System (ESAS) scale. Results: One hundred patients were included in the analysis. Males comprised 65 % of the sample, being 55 % oncological patients. Sublingual fentanyl (71 %), intranasal fentanyl (18 %), oral fentanyl (1 %) and subcutaneous morphine (10 %) were administered. Treatment response was observed in 94 % of patients with improvements of two or more points on the Borg Scale for BD, with no differences between treatments. The safety profile was acceptable in all cases. Conclusions: Although opioids are recommended in the first line of treatment of ID, there is not enough scientific evidence to justify its use. It was observed in the study that fentanyl may be an effective and safe therapeutic option for the control of breakthrough dyspnea in terminally ill patients (AU)

New onset idiosyncratic liver enzyme elevations with biological therapy in inflammatory bowel disease.

BACKGROUND: Anti-tumour necrosis factor α (anti-TNF) agents have been implicated in drug-induced liver injury. There is minimal data on this occurrence in inflammatory bowel disease (IBD) patients. AIM: To identify the characteristics of liver enzyme elevations following anti-TNF therapy initiation in IBD. METHODS: A retrospective cohort of patients initiating anti-TNF therapy were analysed for new onset alanine transaminase (ALT) elevation (≥60 U/L). We collected data on natural history, outcomes and patient characteristics compared with controls with persistent normal liver enzymes. Likelihood of causal association was assessed using the RUCAM score. RESULTS: From 1753 patients initiating an anti-TNF (1170 infliximab, 575 adalimumab, 8 certolizumab), 102 (6%) developed new onset ALT elevation. In 54 (53%), this could be linked to an alternate aetiology. Among those with idiopathic ALT elevations, the median time to ALT elevation from anti-TNF initiation was 18 weeks and median peak ALT was 96 U/L. Six underwent liver biopsy, all demonstrating hepatitis with autoimmune features. Compared to controls, cases were on a lower dose of infliximab (5.7 vs. 6.7 mg/kg, P = 0.02) but were otherwise similar in body mass index, sex and age. On follow-up, 34 continued the anti-TNF, 14 stopped therapy and 4 initiated steroids. Most (85%) normalised their LFTs after a median of 17 weeks including 28 (82%) of those who continued anti-TNF therapy. Ten patients were transitioned to a second anti-TNF without recurrence. CONCLUSIONS: ALT elevations occurred in 6% of IBD patients initiating anti-TNF therapy. Most idiopathic elevations were mild, transient and resolved despite therapy continuation.

Enteric calicivirus and rotavirus infections in domestic pigs.

We report the prevalence of rotavirus and calicivirus infections, along with their respective association with diarrhoea in the porcine population of the region of northern Spain. A total of 221 samples were collected at random from different farms in the region and from the main slaughterhouse facility in the city of Zaragoza. Faecal samples were scored as diarrhoeic or normal and grouped into five groups to match general farm management and age criteria: group I (suckling 0-4 weeks), group II (weaning >4-8 weeks), group III (transition >8-16 weeks), group IV (fattening >16-24 weeks) and group V (adults >24 weeks). Group A rotavirus detection and caliciviruses were investigated by reverse transcription-polymerase chain reaction (RT-PCR). Conventional RT-PCR was performed using primers designed to detect rotavirus group A, caliciviruses and/or human noroviruses. A real-time RT-PCR was carried out using TaqMan probes for genogroups GI and GII of noroviruses. Rotaviruses and caliciviruses were detected with an overall prevalence of 16.7% and 12.2%, respectively. Rotavirus detection in faecal samples was associated with both age and faecal consistency, being more frequent in piglets aged <8 weeks with odds ratios (ORs) equal to 4.3 and 4.9, respectively. Calicivirus shedding in faecal samples was homogenously distributed in all ages, showing no significant association with age or faecal consistency (OR 0.87 and 0.99, respectively). A selection of rotavirus-positive stools were genotyped by multiplex nested PCR. G10, P[6], G12 P[8], G9 [p8] and G4 P[23] genotype combinations were found. Three isolates showed a G3 genotype, but their VP4 gene could not be amplified. It should be noted that the G9 genotype was the major G genotype circulating during that period in Spain. None of the porcine samples was positive for norovirus by real-time RT-PCR, despite the ability of this technique to detect at least 18 human norovirus genotypes. Our data indicate that human noroviruses are unlikely to be circulating in the porcine population; however, sapoviruses have been found. Contrary to rotavirus infection, Calicivirus infection is asymptomatic. Specific primers to detect porcine noroviruses are needed.

Emotional Reactions of Medical Doctors and Students Following the Loss of their Patients at the Dr George Mukhari Hospital Emergency Unit; South Africa

Background: Studies on death and dying predominantly emphasise the needs of the dying patient and the process of bereavement. Few studies have focused on the reactions of medical doctors and students when the patients they have cared for die. Methods: The aim of the study was to explore the thoughts and feelings of doctors and medical students who have lost patients while under their care at the Dr George Mukhari Hospital emergency unit in Ga-Rankuwa; South Africa. The participants included 10 medical doctors and final-year medical students. A qualitative study methodology using a phenomenological approach was used. Results: Meanings were formulated from transcriptions and themes were identified. The following themes emerged: emotional reactions; which included anger; helplessness; guilt and pain; recurrent thoughts about the incident; blame; perceived incompetence; detachment from emotions; religion; death of a paediatric patient; medical training; psychological services; work environment; coping with the family of the deceased; and facing mortality. Conclusion: From the study it was concluded that doctors needed enhanced training in communication skills and communicating death to the patients' families. Bereavement counselling and debriefing should be available to provide them with an opportunity to share emotional responses and reflect on patients' fatality

Emotional Reactions of Medical Doctors and Students Following the Loss of Their Patients at the Dr George Mukhari Hospital Emergency Unit; South Africa

Background: Studies on death and dying predominantly emphasise the needs of the dying patient and the process of bereavement. Few studies have focused on the reactions of medical doctors and students when the patients they have cared for die. Methods: The aim of the study was to explore the thoughts and feelings of doctors and medical students who have lost patients while under their care at the Dr George Mukhari Hospital emergency unit in Ga-Rankuwa; South Africa. The participants included 10 medical doctors and final-year medical students. A qualitative study methodology using a phenomenological approach was used. Results: Meanings were formulated from transcriptions and themes were identified. The following themes emerged: emotional reactions; which included anger; helplessness; guilt and pain; recurrent thoughts about the incident; blame; perceived incompetence; detachment from emotions; religion; death of a paediatric patient; medical training; psychological services; work environment; coping with the family of the deceased; and facing mortality. Conclusion: From the study it was concluded that doctors needed enhanced training in communication skills and communicating death to the patients' families. Bereavement counselling and debriefing should be available to provide them with an opportunity to share emotional responses and reflect on patients' fatality

Prevalence of symptomatic and asymptomatic peripheral arterial disease and the value of the ankle-brachial index to stratify cardiovascular risk.

OBJECTIVES: To determine the prevalence of ankle-brachial index (ABI)<0.9 and symptomatic peripheral arterial disease (PAD), association with cardiovascular risk factors (CVRF), and impact of adding ABI measurement to coronary heart disease (CHD) risk screening. DESIGN: Population-based cross-sectional survey of 6262 participants aged 35-79 in Girona, Spain. METHODS: Standardized measurements (CVRF, ABI, 10-year CHD risk) and history of intermittent claudication (IC), CHD, and stroke were recorded. ABI<0.9 was considered equivalent to moderate-to-high CHD risk (> or =10%). RESULTS: ABI<0.9 prevalence was 4.5%. Only 0.62% presented low ABI and IC. Age, current smoker, cardiovascular disease, and uncontrolled hypertension independently associated with ABI<0.9 in both sexes; IC was also associated in men and diabetes in women. Among participants 35-74 free of cardiovascular disease, 6.1% showed moderate-to-high 10-year CHD risk; adding ABI measurement yielded 8.7%. Conversely, the risk function identified 16.8% of these participants as having 10-year CHD risk>10%. In participants 75-79 free of cardiovascular disease, the prevalence of ABI<0.9 (i.e., CHD risk> or =10%) was 11.9%. CONCLUSIONS: ABI<0.9 is relatively frequent in those 35-79, particularly over 74. However, IC and CHD risk> or =10% indicators are often missing. Adding ABI measurement to CHD-risk screening better identifies moderate-to-high cardiovascular risk patients.

Population dietary habits and physical activity modification with age.

OBJECTIVE: The aim of the present study was to analyse the relation between age and both dietary habits and leisure-time physical activity, and to determine nutrient inadequacy of aged groups in our population. DESIGN: Cross-sectional study. SETTING: A random sample of the 25-74-y-old population of Gerona, Spain. SUBJECTS: A total of 838 men and 910 women were selected from among the general population according to the 1991 census. OUTCOME MEASURES: Analysis of dietary habits, including amount and type of alcohol consumption, and detailed evaluation of leisure-time physical activity. RESULTS: Nutrient densities of carbohydrates, vitamin B(1), vitamin B(12), vitamin C, vitamin E, folate, potassium, iron, magnesium, copper, and dietary fiber increased significantly (P<0.05) with age in both genders, whereas an inverse trend was observed for total fat, saturated fatty acids, cholesterol, and sodium. Multiple linear regression analysis revealed a direct association of healthy dietary habits, characterized through a composite dietary score, with age after adjusting for several confounders both in men and women (P<0.001). This score was composed of folate, vitamin C, vitamin E, beta-carotene, dietary fibre, cholesterol, saturated fatty acids, and sodium. In all, 29 and 10% of male and female subjects aged 65-74 y, respectively, reported inadequate intakes of six or more of 16 nutrients. Total leisure-time physical activity increased with age in men (P<0.002), and was not different among female age groups. CONCLUSION: Dietary behaviours and levels of physical activity spent during leisure time indicate a healthy lifestyle of the aged men and women in the present population. Nutrient inadequacy observed in some aged men and women, however, deserves particular intervention of health-care programmes for this growing part of our society.

An adaptation of the Framingham coronary heart disease risk function to European Mediterranean areas.

AIM: To determine whether the Framingham function accurately predicts the 10 year risk of coronary disease and to adapt this predictive method to the characteristics of a Spanish population. METHOD AND RESULTS: A Framingham function for predicting 10 year coronary deaths and non-fatal myocardial infarction was applied to the population of the province of Gerona, Spain, where the cumulated incidence rate of myocardial infarction has been determined since 1988 by a specific registry. The prevalence of cardiovascular risk factors in this region of Spain was established in 1995 by a cross sectional study on a representative sample of 1748 people. The number of cases estimated by the Framingham function for 10 year coronary deaths and non-fatal myocardial infarction was compared with that observed. The Framingham function estimated 2425 coronary heart disease cases in women and 1181 were observed. In men, 9919 were estimated and 3706 were observed. Recalibrating the Framingham equations to the event rate and the prevalence of the risk factors in Gerona led to estimates very close to the number of cases observed in Gerona men and women. CONCLUSIONS: The Framingham function estimates more than doubled the actual risk of coronary disease observed in north east Spain. After calibration, the Framingham function became an effective method of estimating the risk in this region with low coronary heart disease incidence.

Short-term mortality of myocardial infarction patients with diabetes or hyperglycaemia during admission.

AIM: The hypothesis that patients with hyperglycaemia during admission, regardless of previous diagnosis of diabetes, have worse prognosis than those with normal glucose values is controversial. The objective was to assess the role of hyperglycaemia on short-term mortality after myocardial infarction (MI). METHODS AND RESULTS: A cohort study nested in a prospective registry of MI patients in the reference hospital of Gerona, Spain was performed. All consecutive MI patients under 75 were registered between 1993 and 1996. Patient and clinical characteristics, including previous diagnosis of diabetes, glycaemia on admission and in the next four days, were recorded. Patients with glycaemia on admission or four day mean glycaemia >6.67 mmol/l were considered hyperglycaemic. The main outcome measure was mortality at 28 days. Of 662 patients with MI included, 195 (29.7%) had previously known diabetes mellitus, but 457 (69.0%) had glycaemia >6.67 mmol/l on admission. Patients with hyperglycaemia on admission were older, more often female, more frequently had a previous diagnosis of diabetes, developed more complications, and had higher 28 day mortality. The effect of admission glycaemia >6.67 mmol/l on 28 day mortality was independent of major confounding factors, particularly previous diagnosis of diabetes (OR=4.20, 95% confidence intervals 1.18 to 14.96). CONCLUSIONS: Higher 28 day mortality was observed among MI patients with glycaemia on admission >6.67 mmol/l compared with patients with lower levels, independently of major confounding variables and, particularly, previous diagnosis of diabetes. This early, simple, and inexpensive marker of bad prognosis after MI should prompt the application of more aggressive treatment of MI and risk factors and, probably, of glycaemia during admission.

Membrane conductances of principal cells in Malpighian tubules of Aedes aegypti.

Two-electrode voltage clamp (TEVC) methods were used to explore conductive transport pathways in principal cells, the dominant cell type in Malpighian tubules of the yellow fever mosquito. The basolateral membrane of principal cells had a voltage (V(bl)) of -85.1 mV in 49 principal cells under control conditions. Measures of the input resistance R(pc) together with membrane fractional resistance yielded estimates of the conductance of the basolateral membrane (g(bl) = 1.48 &mgr;S) and the apical membrane (g(a) = 3.13 &mgr;S). K(+) channels blocked by barium accounted for 0.94 &mgr;S of g(bl). Estimates of transference numbers yielded the basolateral membrane Na(+) conductance of 0.24 &mgr;S, leaving 0.30 &mgr;S (20%) of g(bl) unaccounted. The secretagogue db-cAMP (0.1 mM), a known activator of the basolateral membrane Na(+) conductance, significantly depolarized V(bl) to -65.0 mV and significantly increased g(bl) from 1.48 &mgr;S to 2.47 &mgr;S. The increase was blocked with amiloride (1 mM), a known blocker of epithelial Na(+) transport. The inhibition of metabolism with di-nitrophenol significantly depolarized V(bl) to -9.7 mV and significantly increased R(pc) from 391.6 kOmega to 2612.5 kOmega. Similar results were obtained with cyanide, but it remains unclear whether the large increases in R(pc) stem from the uncoupling of epithelial cells and/or the shutdown of conductive transport pathways in basolateral and apical membranes. Our results indicate that the apical membrane of principal cells is more than twice as conductive as the basolateral membrane. Partial ionic conductances suggest the rate-limiting step for transepithelial Na(+) secretion at the basolateral membrane.

Interaction between the Gln-Arg 192 variants of the paraoxonase gene and oleic acid intake as a determinant of high-density lipoprotein cholesterol and paraoxonase activity.

Olive oil, rich in oleic acid, could play a particular beneficial role in the anti-atherogenic effects attributed to the Mediterranean diet. Paraoxonase (PON1) has emerged as the component of high-density lipoproteins (HDL) most likely to explain its ability to attenuate the oxidation of low-density lipoproteins. We hypothesised that oleic acid intake might be associated with changes in PON1-HDL associated particles, and investigated the impact, if any, on this association of the PON1-192 polymorphism, a common polymorphism that strongly modulates PON1 activity. Six hundred and fifty-four men randomly selected from the census were studied. Oleic acid intake was calculated from a 72-h recall questionnaire with specific software. Oleic acid intake groups (low vs. high) were created by stratifying the population according the median value as a cut-point. After adjusting for confounding variables, high oleic acid intake was associated with increased HDL cholesterol levels and PON1 activity only in subjects with the QR and the RR genotypes, respectively. Analyses of the variance showed a statistically significant interaction between PON1-192 genotypes and oleic acid intake for log PON1 activity (P=0.005) and a marginally significant interaction for HDL cholesterol (P=0.066). These results suggest that the beneficial effect of increasing oleic acid intake on HDL and PON1 activity at population level is especially observed in subjects carrying the R allele of the PON1-192 polymorphism.

Physical activity modulates the combined effect of a common variant of the lipoprotein lipase gene and smoking on serum triglyceride levels and high-density lipoprotein cholesterol in men.

Physical activity has been identified as a protective factor against the occurrence and progression of coronary heart disease. The lipoprotein lipase (LPL) HindIII polymorphism has been associated with changes in triglyceride and high density lipoprotein (HDL)-cholesterol levels. We have investigated whether the association between the LPL HindIII genetic polymorphism and lipid levels is modified by physical activity. We have also tested the hypothesis that physical activity may interact with smoking and the LPL HindIII polymorphism to determine an individual's plasma lipid concentrations. A total of 520 men were selected from a representative sample used in a population study conducted in Gerona, Spain. The median value (291 kcal/day) of energy expenditure in leisure-time physical activity of the studied sample was selected as a cut-off to define sedentary or active subjects. Serum HDL-cholesterol was positively and significantly associated with the amount of daily energy expenditure in physical activity, whereas inverse associations were seen between physical activity and triglyceride concentration and with the triglyceride to HDL-cholesterol ratio. These effects were consistent across LPL HindIII genotypes. There was a statistically significant interaction between LPL genotype and smoking on lipid concentrations. No statistically significant differences were observed in lipid levels of active or sedentary non-smokers between H- carriers and H+H+ homozygotes for the LPL HindIII polymorphism. In smokers, sedentary H+H+ homozygotes showed significantly higher triglyceride and lower HDL-cholesterol concentrations than sedentary H- carriers. These differences were smaller and not statistically significant when lipid values of active H+H+ homozygotes were compared with active H- carriers. Among all subgroups, sedentary smokers with the H+H+ genotype had the most adverse lipid profile, which was considerably less adverse in H+H+ smokers who were physically active. These findings suggest that the presence of the H+H+ genotype has a deleterious effect on lipid profile in an adverse environment such as smoking, and that the expenditure of more than 291 kcal/day in physical activity attenuates this effect.

Use of a three-day estimated food record, a 72-hour recall and a food-frequency questionnaire for dietary assessment in a Mediterranean Spanish population.

AIM: To assess the validity and the short-term reproducibility of a semi-quantitative, self-administrated food frequency questionnaire and a structured 72-hour recall in a Mediterranean Spanish population. METHODS: 44 free-living volunteers participated in the study. Macronutrient, vitamin and mineral intake, recorded on the food frequency questionnaire and the structured 72-h recall were compared with intakes derived from a three-day food record (reference method). Validity of the dietary assessment methods was further assessed by comparing urinary nitrogen, plasma vitamin C, plasma beta-carotene and whole blood glutathione peroxidase activity levels with the corresponding nutrient intakes from the questionnaires. The food frequency questionnaire and the 72-h recall were administered twice to assess the short term reproducibility. RESULTS: Pearson's correlation coefficients between urinary nitrogen, plasma vitamin C, plasma beta-carotene and whole blood glutathione peroxidase activity levels and the reported nitrogen, vitamin C, beta-carotene and selenium intakes were 0.26, 0.53, 0.17, 0.26 for the food frequency questionnaire; 0.41, 0.09, 0.34, 0.42 for the structured 72-h recall and 0.50, 0.54, 0.44, 0.38 for the three-day food record, respectively. The short term reproducibility of analysed nutrient intake showed average intra-class correlation coefficients of 0.91 and 0.69 for the food frequency questionnaire and the structured 72-h recall irrespectively. CONCLUSION: The food frequency questionnaire and the structured 72-h recall provide valid estimates of nutrient intake and could be used for dietary assessments.

Role of age and sex in short-term and long term mortality after a first Q wave myocardial infarction.

STUDY OBJECTIVE: The objective of this study was to analyse whether the risk of death within 28 days and three years after a first Q wave myocardial infarction was higher in hospitalised women than in men. DESIGN: Follow up study. PATIENTS AND SETTING: All consecutive first Q wave myocardial infarction patients aged 25 to 74 years (447 women and 2322 men) admitted to a tertiary hospital in Gerona, Spain, from 1978 to 1997 were registered and followed up for three years. MAIN RESULTS: Women were older, presented more comorbidity and developed more severe myocardial infarctions than men. A significant interaction was found between sex and age. Women aged 65-74 had higher early mortality risk than men of the same age (OR 1.62; 95% CI 1.01, 2.66) after adjusting for age, comorbidity and acute complications including heart failure. Women under 65 tended to be at lower risk of early mortality than men (0.45 (95% CI 0.19, 1.04). Three year mortality of 28 day survivors did not differ between sexes. CONCLUSIONS: These data support the idea that the higher 28 day mortality in hospitalised women with a first Q wave myocardial infarction is mainly attributable to the large number of patients aged 65 to 74 years in whom the risk is higher than that in men. Women under 65 with myocardial infarction do not seem to be a special group of risk.

Relationship of age-related myocardial infarction risk and Gln/Arg 192 variants of the human paraoxonase1 gene: the REGICOR study.

Paraoxonase1 (PON1) seems to exert a major antioxidant effect by removing lipid-peroxidation products. A common polymorphism of the PON1 gene, the PON1-192 genetic polymorphism, modulates PON1 activity and has been related in some studies to coronary heart disease. Oxidized LDL is believed to play a crucial role in the pathogenesis of atherosclerosis and there are studies providing support for the oxidative stress theory of aging. We have conducted a case-control study to determine whether PON1 activity and PON1-192 genetic variants have a different impact on myocardial infarction (MI) risk among individuals stratified by tertiles of age distribution. PON1-192 genotypes and PON1 activity were determined in 280 consecutive MI patients and 396 control subjects. Serum PON1 activity levels were significantly higher in controls than in MI patients [226 U/l (159-351) vs. 216 U/l (146-298), median (interquartile range), P=0.005]. A decline of PON1 activity levels with advancing age in subjects carrying the low-activity QQ genotype was observed, particularly in MI patients. PON1 activity and age negatively correlated in MI patients but not in controls. In the entire population, middle-aged and older subjects showed MI risks of 1.89 (P=0.012) and 2.69 (P<0.001) respectively, compared with young subjects. These risks increased to 2.41 (P=0.016) and 4.39 (P<0.001), respectively, in QQ homozygotes in comparison with younger QQ homozygotes, decreased to 1.53 (P=0.314) and 2.08 (P=0.112), respectively, in QR heterozygotes, and also lowered to 1.95 (P=0.410) and 0.51 (P=0.508) in RR homozygotes who were middle-aged and older, respectively, compared with younger RR carriers. The effect of PON1-192 genotypes on the association of the older age-category and MI risk was gene-dosage related. PON1 activity decreases as a function of age in subjects homozygous for the Q allele. Age may also act on MI risk as a function of PON1-192 alleles. The risk of MI increases with advancing age, principally among subjects carrying the low-activity QQ genotype.

Flexibility of the Kir6.2 inward rectifier K(+) channel pore.

Interactions of sulfhydryl reagents with introduced cysteines in the pore-forming (Kir6.2) subunits of the K(ATP) channel were examined. 2-Aminoethyl methanethiosulfonate (MTSEA(+)) failed to modify Cd(2+)-insensitive control-Kir6.2 channels, but rapidly and irreversibly modified Kir6.2[L164C] (L164C) channels. Although a single Cd(2+) ion is coordinated by L164C, four MTSEA(+) "hits" can occur, each sequentially reducing the single-channel current. A dimeric fusion of control-Kir6.2 and L164C subunits generates Cd(2+)-insensitive channels, confirming that at least three cysteines are required for coordination, but MTSEA(+) modification of the dimer occurs in two hits. L164C channels were not modified by bromotrimethyl ammoniumbimane (qBBr(+)), even though qBBr(+) caused voltage-dependent block (as opposed to modification) that was comparable to that of MTSEA(+) or 3-(triethylammonium)propyl methanethiosulfonate (MTSPTrEA(+)), implying that qBBr(+) can also enter the inner cavity but does not modify L164C residues. The Kir channel pore structure was modeled by homology with the KcsA crystal structure. A stable conformation optimally places the four L164C side chains for coordination of a single Cd(2+) ion. Modification of these cysteines by up to four MTSEA(+) (or three MTSPTrEA(+), or two qBBr(+)) does not require widening of the cavity to accommodate the derivatives within it. However, like the KcsA crystal structure, the energy-minimized model shows a narrowing at the inner entrance, and in the Kir6.2 model this narrowing excludes all ions. To allow entry of ions as large as MTSPTrEA(+) or qBBr(+), the entrance must widen to >8 A, but this widening is readily accomplished by minimal M2 helix motion and side-chain rearrangement.

Voltage clamping single cells in intact malpighian tubules of mosquitoes.

Principal cells of the Malpighian tubule of the yellow fever mosquito were studied with the methods of two-electrode voltage clamp (TEVC). Intracellular voltage (V(pc)) was -86.7 mV, and input resistance (R(pc)) was 388.5 kOmega (n = 49 cells). In six cells, Ba(2+) (15 mM) had negligible effects on V(pc), but it increased R(pc) from 325.3 to 684.5 kOmega (P < 0.001). In the presence of Ba(2+), leucokinin-VIII (1 microM) increased V(pc) to -101.8 mV (P < 0.001) and reduced R(pc) to 340.2 kOmega (P < 0.002). Circuit analysis yields the following: basolateral membrane resistance, 652. 0 kOmega; apical membrane resistance, 340.2 kOmega; shunt resistance (R(sh)), 344.3 kOmega; transcellular resistance, 992.2 kOmega. The fractional resistance of the apical membrane (0.35) and the ratio of transcellular resistance and R(sh) (3.53) agree closely with values obtained by cable analysis in isolated perfused tubules and confirm the usefulness of TEVC methods in single principal cells of the intact Malpighian tubule. Dinitrophenol (0.1 mM) reversibly depolarized V(pc) from -94.3 to -10.7 mV (P < 0.001) and reversibly increased R(pc) from 412 to 2,879 kOmega (P < 0.001), effects that were duplicated by cyanide (0.3 mM). Significant effects of metabolic inhibition on voltage and resistance suggest a role of ATP in electrogenesis and the maintenance of conductive transport pathways.

Relationship of abdominal adiposity and dyslipemic status in women with a common mutation in the lipoprotein lipase gene. The REGICOR investigators.

Abdominal obesity constitutes an important risk factor for cardiovascular disease. Hypertriglyceridemia and low high-density lipoprotein (HDL) cholesterol concentration constitute the major lipid alterations observed in obesity. A common variant of the lipoprotein lipase (LPL) gene, the HindIII polymorphism, has been found to be associated with changes in triglyceride and HDL-cholesterol levels. We have investigated the impact of the LPL HindIII polymorphism on the relationship between abdominal adiposity and lipoprotein concentrations in 156 randomly selected women in a cross-sectional study conducted in the province of Gerona, in the northeast of Spain. The waist-to-hip ratio was used as an estimate of regional fat distribution. Serum lipid and lipoprotein measurements as well as lipoprotein lipase-HindIII genotypes were determined. Percentile 50 of waist-to-hip ratio (WHR) (0.81) was used as a cutoff to define low or high WHR groups, which significantly differed in blood pressure and lipid trait concentrations. Serum triglyceride concentrations and mean log triglyceride-to-HDL-cholesterol ratio were significantly higher in H+ homozygous women compared with H- carriers. Whereas no statistically-significant differences were observed in HDL-cholesterol concentration and log triglyceride-to-HDL-cholesterol ratio of H- carriers between WHR groups, H+ homozygous women showed significant differences in these lipid traits. It is noteworthy that high-WHR H- carrier women showed a mean HDL-cholesterol value similar to those of both genotypes in the low WHR group. A statistically significant interaction between WHR and genotype was observed for HDL-cholesterol concentration (P=0. 027) and log triglyceride-to-HDL-cholesterol ratio (P=0.040). These results stress the compensating effects that weight loss may have on women with adverse genetic factors. From a complementary viewpoint, the presence of the H- allele seems to confer a protective lipid profile, even when an adverse anthropometric factor such as abdominal adiposity is present.

Differences in use of coronary angiography and outcome of myocardial infarction in Toulouse (France) and Gerona (Spain). The MONICA-Toulouse and REGICOR investigators.

AIMS: Differences in the management and organization of health services may account for some of the variability in myocardial infarction case fa tality in different geographic areas. The 28-day outcome was compared i n two regions with similar myocardial infarction incidence and mortality rates that had opposing patients in the use of coronary angiography an d coronary revascularization. METHODS AND RESULTS: The 28-day case fatality of patients aged 35 to 64 years with myocardial infarction, surviving the first hour post-admission to hospitals with coronary care units, was compared in the population of myocardial infarction registries of Toulouse, France and Gerona, Spain. Patient characteristics were similar. In Toulouse, 93% of the 819 registered patients underwent coronary angiography compared with only 6% of the 454 in Gerona. Among hospitalized patients 28-day case fatality was 4.3% and 9.3% in Toulouse and Gerona, respectively (P=0.0003). Rates of thrombolysis and beta-blocker use were higher in Toulouse, although severity indicators were similar to those of Gerona. A model adjusted for these variables showed that the risk of death was 1.90 (95% confidence interval: 1.17-3.07) in Gerona patients compared with those of Toulouse. CONCLUSIONS: Routine angiography use is associated with better 28-day myocardial infarction prognosis than restrictive use. However, the optimum proportion of myocardial infarction patients who have to receive angiography procedures remains unclear.